Punch.



J. F,- DOOLITTLE.

PUNCH. I

APPLICATION FILED FEB. 26, 1908.

900,009, w 0 PatentedvSept. 29,1908.

UANLJJJJJJ DLAIES PAIEN T JOHN F. DOOLITTLE, OF CLEVELAND, OHIO,ASSIGNOR TO THE CLEVELAND STEEL TOOL COMPANY, OF CLEVELAND, OHIO, ACORPORATION OF OHIO.

PUNCH.

To all whom it may concern:

Be it known that I, JOHN F. DooLrrTLE, a citizen of the United States,resident of Cleveland, county of Ouyahoga, and State of Ohio, haveinvented a new and useful Improvement in Punches, of which the followingis a specification, the principle of the invention being hereinexplained and the best mode in which I have contemplated applying thatprinciple, so as to distinguish it from other inventions.-

This invention relates, as indicated, to punches, by which term it isdesired to designate not merely tools designed primarily for strictlypunching operations, as for the punching of rivet holes and the like insheet metal and structural material, but also any form of similar toolsuch as is used for setting rivets and forming or bending metallicarticles. All such tools are intended to be likewise included in thedesignation.

The object of the invention is the provision of an improved form ofcoupling for securing the punch tool to the shank of the plunger, orholder, whereby the tool proper is designed to be forced to or throughits work.

To the accomplishment of this and related objects, said invention, then,consists of the means hereinafter fully described and particularlypointed out in the claims.

The annexed drawing and the following description set forth in detailcertain mechanism embodying the invention, such disclosed meansconstituting, however, but one of various mechanical forms in which theprinciple of the invention may be used.

In said annexed drawing: Figure 1 represents a side elevation of aplunger shank and punch tool aflixed thereto by a coupling embodying myseveral improvements; Fig. 2 is a central vertical section of the same;Fig. 3 is a perspective view of a clamping member forming an element ofsuch structure, and Fig. 4 is a vertical sectional detail View showing aslightly modified construction in the form of the punch tool andclamping member.

The shank A of the plunger to which the punch tool A is designed to beaffixed is of the usual construction, its lower end a being threaded forsome distance to permit the screwing thereto of the coupling nut A Theexterior form of such coupling nut is a matter of indifference; thelower portion of its bore 61/, however, is tapered as shown inSpecification of Letters Patent.

Application filed February 26, 1908.

Patented Sept. 29, 1908.

Serial No. 417,832.

Fig. 2. Fitted to this tapered portion of the coupling is a clampingmember A', which constitutes one of the features of the device. Suchmember comprises an annular sleeve,

Fig. 3, the exterior form of which, as indi- 1 I the length of thesleeve whereby it is rendered compressible more or less after thefashion of a chuck. It will accordingly be seen that when the punch toolis placed therein and the member thereupon attached to the lower end ofthe plunger shank by the coupling nut, the effect of drawing up thelatter will be to cause it to firmly grip the body of the punch tool andsecurely retain the same against movement or dislodgement.

While with my improved clamping device I am enabled thus securely toattach the punch tool to the shank, I find that the security of theconnection of the tool to the shank is increased by flanging the upperend of the tool' body and beveling or reaming a corresponding portion atof the bore in the I clamping sleeve to receive such flange or shoulderof. The work may then be stripped from the projecting portion of thetool without any danger of the latter being loosened in its seat whichmight render the tool more liable to fracture. The shoulder a Ipreferably form by rolling down the end of the tool body since thereby aconsiderable saving of material is effected over the prevailing methodof forming shoulders on tools of this sort by machining them down, whileobviously a corresponding saving of time and labor is effected. A veryslight shoulder serves every purpose in View of the effective clampingaction of the annular sleeve when constructed as set forth.

Since it is the metal formerly constituting the edge of the punch bodythat is rolled down to provide shoulder (1 such edge it will be seen isrounded off and the upper end of the bearing surface of the bodycorrespondingly reduced, such end being in eifect given a slightlyconvex conformation. This serves still further to distinguish the construction in hand from the present type of shouldered punch tool; for bythis means the shoulder escapes the compression strain incident to thedownward, or operative,

movement of the device, being subject only to gtheyrelatively light dutyof holding the tool against dislodgment when the work is strippedtherefrom.

aWith the old form of tools, particularly after the lower end of theholder or shank A has become battered with use, it is not infrequent forthe shoulder to be broken off bodily from the tool by the shearingstress to which it is subjected.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the mechanismherein disclosed, provided the means stated by any of the followingclaims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as myinvention 1. In a device of the character described, the combination ofa shank, a coupling adapted to be secured to the end of said shank, thelower portion of the bore in such coupling being tapered, a tool, and anannular clamping member fitted to the lower portion of said couplingbore and adapted to receive said tool, said clamping member beingalternately slitted from opposite ends.

2. In a device of the character described, the combination of a shank, acoupling nut adapted to be threaded onto the end of said shank, thelower portion of the bore in such coupling nut being tapered, a tool,and an annular clamping member fitted to the lower portion of the borein said coupling nut and adapted to receive said tool, said tool havingits upper end formed with a shoulder and the upper end of the bore insaid clamping member being beveled to receive such shoulder, suchshoulder lying below the end of the tool and the latter having itsbearing surface reduced, whereby the strain is brought within the bodyof the punch when the device is in operation, substantially asdescribed.

3. In a device of the character described, the combination of a shank, acoupling nut adapted to be threaded onto the end of said shank, thelower portion of the bore in such coupling nut being tapered, a tool,and a clamping member comprising an annular sleeve fitted to the lowerportion of the bore in said coupling nut and adapted to receive saidtool, said tool having its upper end rolled down to form a slightshoulder, and said clamping member being alternately slitted fromopposite ends and having the upper end of its bore reamed out to receivesuch shoulder.

4. In a device of the character described, the combination of a shank, acoupling nut adapted to be threaded onto the end of said shank, thelower portion of the bore in such coupling nut being tapered, a tool,and an annular clamping member fitted to the lower portion of the borein such coupling nut and adapted to receive said tool, the upper edge ofthe body of said tool being rolled down to form a slight shoulder, andthe upper endv of the bore in said clamping member being reamed out toreceive the shoulder thus formed, the upper end of such punch bodyhaving its bearing surface reduced, whereby the strain is brought withinthe body of the punch when the device is in operation, substantially asdescribed.

5. In a device of the character described, the combination of a shank, acoupling nut adapted to be threaded onto the end of said shank, thelower portion of the bore in such coupling nut being tapered, a tool,and a clamping member comprising an annular sleeve iitted to the lowerportion of the bore in said coupling nut and adapted to receive saidtool, the upper edge of the body of said tool being rolled down to forma slight laterally projecting shoulder, said clamping member beingalternately slitted from opposite ends and having the upper end of itsbore reamed out to receive such shoulder, the upper end of such punchbody being left rounded, whereby the strain is brought within the bodyof the punch when the device is in operation, substantially asdescribed.

6. In a device of the character described, clamping means comprising thecombination with a threaded coupling nut having the lower portion of itsbore tapered, of an annular sleeve iitted to such lower portion of suchbore and alternately slitted from opposite ends.

7. As a new article of manufacture, a punch tool including a punch bodyhaving its upper edge rolled down to form a slight laterally projectingshoulder, the upper end of such body having its bearing surface reduced.

Signed by me this 19th day of liebruary,

JOHN F. DOOLIPHJE. Attested by MARY ISRAEL, JNo. F. Chairman.

